A 35-year-old man with lepromatous leprosy on multidrug therapy (MDT) for 3 months presents with acute onset of painful nodules, fever, and arthralgia. Examination reveals tender erythematous nodules on extensor surfaces and ears. What is the most appropriate next step in management?

Explanation

## Clinical Diagnosis This patient presents with **Erythema Nodosum Leprosum (ENL)**, a Type III hypersensitivity reaction (immune complex-mediated) occurring in lepromatous and borderline lepromatous leprosy patients, typically during or shortly after MDT initiation. **Key Point:** ENL is characterized by painful nodules, fever, arthralgia, and systemic symptoms — distinct from the Type I reaction (reversal reaction) which causes acute inflammation of existing lesions. ## Management of ENL ### First-Line Approach **High-Yield:** The cornerstone of ENL management is **continuation of MDT** combined with **immunosuppression**: 1. **Continue MDT** — stopping treatment allows bacillary load to increase and perpetuates ENL 2. **Systemic corticosteroids** — prednisolone 0.5–1 mg/kg/day, tapered over 12–16 weeks 3. **Thalidomide** — 100–400 mg/day (if available and approved), especially for recurrent or steroid-dependent ENL **Clinical Pearl:** Thalidomide is highly effective in ENL (>90% response) because it suppresses TNF-α production and restores cell-mediated immunity. However, it is teratogenic and requires strict contraception and informed consent. ### Management Algorithm ```mermaid flowchart TD A[ENL suspected]:::outcome --> B{Confirm diagnosis}:::decision B -->|Clinical + histology| C[Continue MDT]:::action C --> D[Start prednisolone 0.5-1 mg/kg/day]:::action D --> E{Response at 4-6 weeks?}:::decision E -->|Good| F[Taper steroids over 12-16 weeks]:::action E -->|Poor or recurrent| G[Add thalidomide 100-400 mg/day]:::action G --> H[Monitor for teratogenicity]:::action ``` ### Adjunctive Measures - NSAIDs for pain and fever - Aspirin for neuritis prevention - Supportive care (rest, elevation of affected limbs) - Regular monitoring for complications (iridocyclitis, neuritis, orchitis) **Warning:** Do NOT stop MDT — this worsens ENL and allows relapse of leprosy. Stopping treatment is a common exam trap. [cite:Park 26e Ch 8] ## Why Other Options Are Incorrect | Option | Why Wrong | |--------|----------| | Stop MDT immediately | Discontinuing MDT allows bacillary multiplication and worsens ENL; it is contraindicated | | Perform biopsy and defer treatment | While histology confirms ENL (foamy macrophages, immune complexes), clinical diagnosis is sufficient to start treatment; delaying steroids allows disease progression | | Switch MDT regimen | ENL is not due to drug resistance; changing MDT is unnecessary and harmful |